Machine tool



Aug. 15, 1944. E. P. BULLARD, 3D., ETAL I 5,

I MACHINE TOOL Filed July 16, 1940 I4 Sheets-Sheet 3 ATTOR Aug. 1.5, 1944.

E. P. BULLARD, 3b., ErAL MACHiNE TOOL Filed July 16, 1940 14 Sheets-Sheet 4 [NV TORS $357? 9 E. P." BULLARD, 3b., a-rAL 2,355,625

MACHINE TOOL 1944- 1-; P. BULLARD, an EIAL 2,355,625

MACHINE TOOL- Filed July 16. 1940 14 Sheets-Sheet 6 Aug. 15, 1944.

E. P. BULLARD, 3b., ETAL 2,355,625

' mcamn TOOL Filed July 16, 1940 14 Sheets-Sheet 8 14 Sheets-Sheet 9 MACHINE TOOL E. P. BULLARD, 30., ErAL FiIed'Julv 16 Aug. 15, 1944.

\ amaummwmv 3W E. P; BULLARD, 3b., EI'AL MACHINE TOOL Filed July 16; 1940 14 Sheets-Sheet 1,0

1944' E. P; BULLARD, 30., ETAL' 2,355,625

MACHINE TOOL Filed July 16, 1940 14 Sheets-Sheet 11 INVENTORS 5a M/Wr l-l, ZJJ fER ATTOW Aug.- 15, 1944.

E. P; BULL/5RD, 3b., ETAL MACHINE TOOL Filed July 16. 1940 14 Sheets-Sheet 12 Aug. 15, 1944. E. P. BULLARD, 30., ET AL 2,355,525

' MACHINE TOOL Filed July 16, 1940 14 Sheets-Sheet 13 INVENY Q R S NEY an? J Aug. 15,1944.

E. F. BULLAR D, 3D.. ETAL MACHINE TOOL Filed July 16, 1940 14 Sheets-Sheet 14 Patented Aug. 15, 1944 MACHINE TOOL Edward P. Bullard, III, Fairfleld, Frank H. Mussler, Stratlord, Paul H. Lange, Bridgeport, Edward N. Cowell, Stratford, and Leroy E. Alvey, Bridgeport, Conn, assignors to The Bull'ard Company, a corporation of Connecticut Application July 16, 1940, Serial No. 345,772

86 Claims.

This invention relates to machine tools, and particularly to the elass of machine tools that are capable of performing numerous operations either independently or simultaneously on work.

Although the principles of the invention may be applied to many types of machine tools, they will be shown and described as applied to the class including lathes and boring mills.

Among the objects of this invention include,

the provision of a machine tool having a spindle drive, and a housing therefor rigidly secured substantially wholly within the frame of the ma-- chine in a manner to prevent its twisting due to the torque developed between the drive and the spindle during operation; the provision of a variable-speed transmission for a machine tool in which constantly meshing gear combinations are provided that are adapted to be engaged and disengaged by internal-external positive-action clutches so as not to impair the quietness or smooth operation of the transmission; the provision of a variable-speed transmission for a ma! chine tool having less gears than the number of speeds the transmission is capable of producing,

and in which all speeds are in geometrical proportion; the provision of a machine tool having a variable-speed transmission for a work-supporting table, and gear shifting levers for the transmission located in a position convenient for the operator but out of the way of the table; the provision of a machine tool having a variablespeed transmission in which the main clutch can' be engaged only when a gear train is fully meshed; the provision of a machine tool having a feed-works transmission for each tool-supporting head, all of which are interchangeable; the provision of a feed-works transmission for a machine tool having a common lever for engaging the forward or reverse feed and traverse drives for each path along which the tool support is adapted to be moved; the provision of a feedworks transmission for a machine tool having hand wheels for manual control of the tool heads, and feed and traverse clutch shifting levers arranged along the axes of the hand wheels; the provision of a variable-speed feed-works transmission including sliding gears .for varying the rate at which the tool supports are fed; the provision of a machine tool feed-works transmission including an interlock to prevent the engagement of the feed or traverse clutch when the otheris in engagement; the provision of a feedworks transmission for a machine tool having manually-operable hand wheels that are automatically disengaged from the transmission when the latter is set for moving the tool support at traverse speed; the provision of a feedworks transmission having axially-shiftable oscillatable means for changing the feed of the transmission and located in a position readily observed and reached from the normal position of the operator; the provision of a machine tool having a plurality of tool supports each adapted to be moved along intersecting aths by a feedworks transmission and having shift levers, the

directional movements of which correspond to the direction ofmovement of the tool supports;

the provision of-amachine tool in which the tool heads are adapted to be moved along intersecting paths, and in which they can be moved along a line that bisects the angle between said paths by simultaneously engaging the feed drives for moving said tool headsalong each of their paths; the provision of a machine tool having a plurality of tool supports, the movements of which are automatically stopped 'at any redetermined points along their paths of travel; the provision of a machine tool in which all feeds forthe tool heads may be engaged and disengaged, and their direction of operation changed while the work'- supporting spindle is rotating; the-provision of a lowered while the machine is operating; and the provision of a lathe having such a cross-rail, the movement of which will automatically stop when it reaches a predetermined high or low .point, and if it should approach too near the side head of the lathe;

features of the invention will become apparent from the following specification and accompanying drawings, in which:

Figure 1 is a perspective view of a vertical turret lathe to which the principles of the invention have been applied;

Figure 2 is a side elevational view of the lathe shown in Figure 1, certain arts being removed and others being broken away to illustrate features of the invention;

Figure 3 is an elevational view of a portion of the lathe shown in Figure 2 with certain parts broken away to show a detail of construction;

Figure 4 is a front elevational view of a portion of the lathe shown in Figure 1, parts being broken away to disclose the drive for the side head;

Figure 4-A is a side elevational view of a portion of the lathe of Figure 1, showing the drive for the side head;

Figure 5 is a sectional elevational view of the The above, as well as other 'objects and novel head stock transmission for the work-supporting table of the lathe shown in Figure 2;

Figure 6 is a top plan view of the headstock transmission shown in Figure 5, and of its gear shifting mechanism;

Figure 7 is a top plan viewof the gear-shift lever arrangement for the gear shifting mechanism of Figure 6; A

Figure 8 is a sectional elevational view taken substantially along the lines 8-8 of Figures 6 I and 7;

Figure 9 is a sectional elevational view taken substantially along line 99 of Figure 6;

Figure 10 is a sectional elevational view taken substantially along line Il0 of Figure 6;

Figure 11 is a sectional elevational view taken substantially along lines Il-ll of Figures 6 and 8;

Figure 12 is a sectional elevational view taken substantially along line l2-l 2 of Figure 6;

Figure 13 is a sectional elevational view taken substantially along lines l 3l 3 of Figures 6 and 8;

Figure. 14 is a. sectional elevational view taken substantially along lines I4 l4 of Figures 6 and 8;

Figure 15 is a sectional elevational view taken substantially along line |l5 of Figure 8;

Figure 16 is a sectional elevational view taken substantially along line |6l5 of Figure 8;

Figure 17 is a sectional elevational view taken substantially along line ll-Il of Figure 6;

Figure 18 is a sectional plan view taken substantially along line l8l8 of Figure 1;

Figure 19 is a sectional elevational view taken substantially alon the line l9-l9 of Figure 2;

Figure 20 is a side elevational view of the feedworks Ft of Figure 2, the side plate being broken away and certain elements omitted to clearly show certain features of the invention;

Figure 21 is a sectional elevational view taken substantially along line 2|2l of Figure 20;

Figure 22 is a front elevational view of the feedworks Ft of Figure 2, certain parts being broken line 26-46 of Figure 25.

Figure 27 is a sectional elevational view taken substantially along line 2'I2| of Figure 4; and

Figure 28 is a sectional elevational view taken substantially along line 2828 of Figure 4.

General organization Referring to the drawings and particularly to Figs. 1, 2 and 4, the principles of the invention are shown as applied to a vertical turret lathe comprising a standard S to the bottom of which a base B is integrally connected. A rotatable work-supporting table W is mounted on the base B and is provided with a spindle suitably journaled in bearings within the base. Referring to Figure 2, a headstock transmission T is mounted substantially wholly within the lower part of the standard S, driven by a motor M (Fig. 1) and adapted to rotate the table W at a plurality of speeds.

A cross-rail C is mounted on the front of the standard S and supports a ram-head Hr and a turret head Ht. The rail C is adapted to be moved vertically along the standard S, while the heads Hr and Ht are individually adapted to be moved along intersecting paths. The movements of the heads Hr and Ht are controlled by separate variable-speed feed-works transmissions Fr and Ft mounted on opposite ends of the cross-rail C. A side-head H5 is mounted on one front corner and side of the standard S and it is adapted to be moved vertically and horizontally by an additional feed-works transmission F5.

All of the feed-works are standardized so that identical constructions are employed. They are all interchangeable although the bracket for the feed-works Fr is left-handed rather than right. The transmission T (Fig. 2) supplies power for all the feed-works through suitable gearing and shafting that extends upwardly from the center of the standard S to a gear bracket G on the top thereohthence outwardly to each side of the machine where the shafting is connected to a pair of vertically-disposed splined shafts that extend downwardly on the one side through both feed-works Ft and F5 (Fig. 4) and on the other side through the feed-works Fl- (Fig. 1). The gear bracket G also includes a clutch-operated mechanism for controlling the vertical movement of the rail C along the standard S.

An intercontrol is provided for preventing the rail C being moved either upwardly beyond a definite limit or downwardly below a definite limit, as well as for terminating its downward movement when it approaches dangerously close to the side-head H5. 1

Each of the tool-heads Hr, Ht and H5 is provided with a feed knock-out Kr, Kt and Ks, respectively, comprising adjustable abutment members adapted upon actuation toenergize an electrical circuit that controls a fluid-operated thrustor for instantly neutralizing the feed clutches of the respective feed-works Fr, Ft and F5.

Referring to Fig. 2, the standard S comprises a substantially hollow vertically-disposed housing 50, provided with bearing supports for the transmission ,T. Machined ways 5| are located on each inner side wall of the standard S and form bearing surfaces to receive flanged guide bearings 52 located on each side of the housing for the transmission T.

The base B comprises a substantially cylindrical shell 53, integral with the forward end of the standard S. The combined standard and housing 53 are cast integrally and provided with a cored-out portion forming an-opening 54 be tween the standard S and the housing B. The walls formed by the cored-out portion provide bearings 55 on each side of the opening 54 adapted to receive flanged bearing plates 55 on each side of the forward end of the housing for the transmission T. The bearings 55 and 5| support the transmission T. The bearings 5| and 52 extend substantially the full length of the transmission housing absorb all tortional stresses and prevent twisting of the housing when the transmission T is under excessive loads. Additionally, this construction enables bodily axial adjustment of the transmission, facilitating the establishment of radial alignment and a proper driving relation between the transmission T and a the table W..

The table W comprises a cylindrical member 51 having radially disposed T slots 58 located on its top surface. The slots 58 are adapted to re-" ceive clutch jaws for securing work to the table. The table is provided with a spindle that extends downwardly within the'base B and journaled in suitable bearings therein.

Headstock transmission Referring to Figs. and 6, the transmission T comprises a driving shaft 59 that is driven from the motor M (Fig. 1) through a multiple V pulley 59 (Fig. 6).- The pulley 88 is keyed to an extended hub portion of a clutch-driving element 84 that is joumaled in the end wall of a housing 52 (Fig. 2) attached to the rear of the standard S. The hub of the element 84 is recessed to provide a bearing for the drive shaft 59. The drive shaft- 59 supports a multiple-disc friction clutch 53, the discs of which are provided with'peripheral teeth. The clutchdriving element 84 (Fig. 6) is provided with internal teeth adapted to mesh with the teeth on the periphery of the friction discs of clutch 83. A spur gear 8| is also keyed to the hub of element 84 for a purpose to be described later. A friction brake 85 is likewise supported on the drive shaft 59, and comprises a friction disc 55 having peripheral teeth adapted to mesh with the internal teeth disposed about an Opening in a bracket 61, (Figs. 2 and 6) fixed to the end wall of the standard S. Both the clutch 83 and thebrake 85 are provided with metal discs splined to the drive shaft 59 on each side of the friction discs. the shaft 59 between the clutch 53 and the brake 55, and supports a slidable grooved spool 89. Toggle connections 18 and II are provided between the spool 69 and certain of the movable metal discs of the clutch 63 and brake 85 whereupon axial movement of spool 89 alternately engages and releases the clutch and brake.

The transmission T is adapted to drive the mission T.

Referring to Fig. 5 the above desired features have been obtained by employing, in the transmission, a primary unit Pu, a secondary unit Sn and a tertiary unit Tu. These units are designed and constructed so that only parallel shafts are employed throughout the transmission, and cer- A sleeve 88 surrounds tain gears'are common to various units. Additionally, the gear combinations of the various units are designed so that the different speeds of the transmission will increase substantially in accordance with a geometrical progression. When it is desired .to cover a specific range of speeds, with a given number of changes of speed, itis first necessary to determine the geometrical constant for the desired speed range. This is determined by multiplying the lowest desired speed by the geometrical constant raised to a power equal to the number of desired changes of speed minus 1 and letting that product equal the maximum speed desired from which equation the geometrical constant may be obtained.

The gear combinations of the various units are designed so that the ratio of any gear combination in the primary unit Pu divided by the ratio of a gear combination therein which produces the next lower speed in said primary unit is equal to Four spur gears l2, 13, I4 and 15 are freely journaled on the drive shaft '59, and each gear is provided with positive-action clutch-engaging teeth arranged between gears 12, I3, and l4, l5. Slidable gear-engaging means .16 and "are keyed to the driving shaft 59 and are located between respective gear sets 12, I3, and l4, 15. Thus, movement of the engaging means l8, 11 to the left or to the right as viewed in Fig. 5 will respectively connect shaft 59 to either gears 13, 15 or gears I2,

14. A shaft'l8 parallel with shaft 59 is prov.ded in the transmission and is adapted to support four gears 19, 88, 8| and 82 arranged in units of two. These last-mentioned gears are keyed to the shaft 18 and each is retained in constant mesh with gears 12, I3, 14 and 15 respectively. The gears 12, 13, 14 and I5, and 19, 80, BI and 82 comprise the primary unit Pu of the transmission T.

An additional parallel shaft 83 is provided in the transmission T on which gears 84 and 85 are freely journaled. The gears 84 and 85 are likewise provided with positive action'clutch-engaging teeth on adjacent sides. A positive-action gear-engaging means 86 is keyed to the shaft 83 and is provided with a slidable element for selectively engaging the gears 84 and 85. The gear 84 on shaft 83 is adapted to be maintained in constant mesh with the gear 88 on shaft 18, while the gear 85 on shaft 83 is adapted to-be maintained in constant mesh with an additional gear 81 integral with shaft 18. Gears 84, 88, 85, and 81 comprise the secondary unit Su. The shaft 18 acts as a common shaft between the primary and secondary units, and gear serves a dual function in meshmeans 18 and I1, shaft 18 can be driven at four separate and distinct speeds from the drive shaft 59. Furthermore, the shaft 83 may be driven at eight separate and distinct speeds from the drive shaft 59 byselectively shifting the mean 16, I1 and 86.

The shaft 83 of the secondary unit is extended and forms one shaft of the .tertiary unit Tu. The extended portion of shaft 83 is provided with gear teeth" 88 adapted to be maintained im'constant mesh with a gear 89 freely joumaled on a driven shaft 98 forming the other shaft of the tertiary unit Tu. Likewise, an extended portion of shaft 83 fixedly-supports a gear 9| adapted to be maintained in constant mesh with a gear 92 freely journaled on a sleeve keyed to the driven shaft 98. Each of the gears 89 and 92 are provided with positive-action clutch-engaging means facing each other and disposed between the two gears. A shiftable engaging-means 93, splined to the sleeve on which gear 92 i journaled, is provided between the last two gears for selectively engaging either. In as much as the shaft 83 may be driven at eight different speeds from the driving shaft 59, it follows that selectively shifting the means 93 of the tertiary unit Tu will impart sixteen separate and distinct speeds of rotation to the driven shaft 98.

The driven shaft 98 is arranged co-axially with The end of driven shaft 90 adjacent the gear 81 is provided with a spline 94. An internal ring gear 95 is splined on the end of driven shaft 90 and is adapted selectively to be moved axially to directly connect driven shaft with the shaft I9'the internal teeth of ring gear 95 meshing with the extended external teeth of gear, 81.

From an inspection of Fig. 5, it is apparent.

that the driven shaft 90 may be driven at twenty different speed while employing gears that remain constantly in mesh with their mating gears, thereby avoiding the difficulties encountered, with constructions employing divin keys. Furthermore, the use ofthe common shaft between the secondary and primary units as well as common gears between units, together with the arrangement of the driven shaft 90 coaxial with shaft I8 of the primary and secondary units, tends to reduce to a minimum the number of gears in the transmission for a given number of different speeds of the driven member. Additionally, each gear combination in the primary, secondary and tertiary units is so designed that it may be used with any other gear combination in any unit and the ability to employ the various gear combinations of each unit over and over, further minimizes the number of gear combinations required for a given number of specific speeds of the driven shaft 90. r

The driven shaft 90 is provided with a bevel gear 96 at its end opposite that which contains spline 94. This bevel gear 95 meshes with a bevel ring-gear 91 (Fig. 2) fixed to the under surface of the work-supporting table W.

The various gear combinations of the primary, secondary and tertiary units are selectively engaged and disengaged by the shiftable means I6,-

ing bracket 98 (Fig. 6) and connected to said shiftable elements through linkages to be described. Referring to Fig. 6, the bracket 98 comprises a relatively flat irregular-shaped box-like element 99 adapted to be bolted to the bottom of the standard S. The walls between the box andthe standard are provided with openings through which a series of six reciprocable rods I00, IOI, I02, I03, I04 and I05 are adapted to pass.

Referring to Figs. 5 and 6 the rod I00 extends into the standard Slto a point on the far side of the transmission T and is connected to a link I06 that is fixed to a vertically-disposed shaft I01. The upper end of the shaft I01 has fixed to it a link I08 which forms a bell-crank with the link I06. Link I08 is connected to a link I09 which in turn is connected to a link IIO fixed to the vertically-disposed shaft II4 extending upwardly within the standard S to a point adjacent the' primary unit Pu. The upper end of the shaft I I4 rigidly supports a yoke I I5, that engages the shiftableelement 'II.

The rod I02 is pivoted to a link II6 that is rigidly connected to a vertically-disposed shaft III. The shaft II'I extends vertically within the standard S to a point near the top of the transmission T. The upper end of shaft II I fixedly supports a link II8 that is pivoted to a pull rod II9 connected to an arm of an oscillatable yoke I20. The yoke engages the spool 69 on the driving shaft 59 between the clutch 83 and brake 55.

Rod I03 extends into the standard S where it is connected to a link I2I fixed to a pivot shaft I22. The pivot shaft I22 has rigidly fixed thereto a yoke I23 which is adapted to en e the shiftable element 86 of the secondary unit Sn.

Rod I04 extends into the standard S to the far side of the transmission T where it is connected to a link I24 rigidly fixed to a pivot shaft lower end of a shaft I I. The upper end of shaft III fixedly supports a yoke II2 that engages the shiftable element I5 so that reciprocable movement of the rod I00 moves the element I6 to the right and left thereby selectively connecting connected to a link I2'I fixed on a pivot shaft,

I 28. The shaft I28 rigidly supports a yoke I29 that engages the shiftable element 93 of the tertiary unit Tu.

Fromthe foregoingit is apparent that selective reciprocation of the rods I00; IOI, I03, I04 and I05 will set up various gear combinations in the transmission T to provide twenty different rates at which the driven shaft may be rotated.

Referring to Fig. 6, the rod I00 is connected'to a rack I30 within the box 99 by a crank member I3I that is pivoted on a vertically-disposed shaft I32 (Fig. 9). The crank I3I includes a rigid arm I33 that forms a cross-head pivotal-connection with one end of the angularly related rack I30 which insures substantially axial movement of the rod I00 for limited motion of rack I30. The cross-head pivotal connection includes a square slide I34 (Fig, 6) pivoted to the arm I33 of crank I3I, and adapted to slide in a transverse slot in the one end of the rack I30. Similarly, rod IN is connected to a crank I35 which likewise is pivoted on the shaft I32, and a rack I38 is connected to crank I35 in the same manner as rack I30 is connected to the crank I3I (see Fig. 11). Rods I03 and I 04 are similarly connected to racks I 31 and I38 through cranks I39 and I40, respectively, in the same maner as racks I30 and I36 are connected to cranks I3I and I35.

The rod I02 which actuates the clutch 53 and brake 55 is connected to a bell-crank lever I located in the box 99. The lever I4I is pivoted on a vertically-disposed shaft I42, to which is also fixed a relatively long hand-operated lever I43. Referring to Fig. 1, additional main clutch operating levers I43a and I43b are provided, the former for foot actuation and the latter located on the left side of the machine.

The rod I05 which actuates the shiftable element 93 of the tertiary unit Tu is connected to a bell crank lever I44 pivoted within the box 99 on a vertically-disposed shaft I45. The opposite end of the bell c'rank I is connected to a bearing I45 to be described later. The racks I30, I85, I31 and I38 are adapted to be reciprocated along their longitudinal axes, while the bell crank I44.

is adapted to be pivoted about the shaft I 45 by a movement of bearing Him a direction transversely to the movement of said racks I30, I36, I31 and I38.

Referring to Figs. 6 and 8 of the drawings, the racks I30 and I36 are adapted to be reciprocated separately and selectively by a' common driver mesh with rack teeth formed on the under sides of racks I30 and I36. Each of the legs of the yoke I49 is provided with gear teeth I50 which are adapted to mesh with the rack teeth on the racks I30 and I36. Oscillation of the shaft I48 of the rack I30 or, I36 which is not in driving engagement with the driver I41. Accordingly, by shifting the shaft I48 axially and then oscillating it, the racks I30 and I36 can be selectively reciprocated to actuate the shiftable elements 16 and 11 of the primary unit Pu.

From an inspection of Fig. 5, it is apparent that shiftable elements 86 and 93 must be in engagement with'one of the gear combinations of the secondary and tertiary units at the same time in order to impart a drive to the driven shaft 90 through said secondary and tertiary units. Accordingly, the rods I03 and I65 of Fig. 6 must be actuated simultaneously in order to effect driving of the driven member through the secondary and tertiary units. Referring to Fig. 8, a relatively long sleeve II extends into the box 99 and telescopes the relatively long shaft I48 The sleeve l5I is provided with two bearing elements, namely, the bearing I46 and another bearing I52, both of which permit axial shifting of said sleeve relatively to shaft I48, as well as oscillating movement of said sleeve. The bearing I46, which is fixed to the bell crank I44 (Fig. 6), is also fixed to the sleeve I5I. The bearing element I52 includes a relatively long gear porneutral position,it is apparent that the reciprocation of link I04 should only occur when the bearing I46 is in said neutral position. This has been accomplished by providing aspacing sleeve I54 on the sleeve I5I on which a driving element I55 is journaled. Referring to Figs. 6, 8 and 14, the element I55 comprises .a sleeve having a gear portion I56 formed on its periphery. It is also provided with a peripheral slot I51 that cooperates witha pin I58, fixed to the box 99, to permit limited oscillation and to prevent axial movement of the element-I55. Driving element I55 is further provided with a pair of diametrically-disposed ears I59 (Fig. 13) which are adapted to engage the side walls of a slot I60 in a connecting element I6I (Fig. 8). The element I6I is fixed to the sleeve I5I and is provided with an undercut recessed portion I62 into which the ears I59 of the driving element I55 are adapted to pass upon axial shifting of the sleeve I5I beyond a predetermined point. The arrangement and construction permits the ears I59 to engage the side walls of the slot I60 in the element I6I only when the bearing I46 is in its neutral position. Axial shifting of bearing I46 to either side of this neutral position will prevent ears I59 from engaging the side walls 'of slot I 60 in the element I6I. Therefore, the sleeve I5I may be selectively shifted axially and oscillated to transmit the drive of the primary through the secondary and tertiary units on the one hand, and to transmit said drive directly to the driven shaft 90 as desired. v

Referring again to Fig. 8, the sleeve I5I and shaft I48 are adapted to be axially shifted and oscillated by hand Revers I63 and I64 respectively. These levers are constructed and arranged to transmit their movement in an amplified form to the shaft I48 and I5I, and to prevent the pas- V sage of dirt and chips into, or the leakage of lubricant from within the box 99. Referring to Fig.

16, a spherical portion I65 is provided between the ends of hand lever I64 that forms a ball and socket fulcrum with a cover plate I66 for box this entire axial movement of sleeve I5I, the rack I31 will be in positive mesh with the gear segment I53. his arrangement permits the reciprocation of the rack I31 to cause the element 86 of the secondary to engage either gears 84 or 85 whenever gears 92 or B9 are engaged by the element 93, thus completing a driving train through the secondary and tertiary units to the driven shaft 90.

Reciprocation of the rod I94 within the box 99 Fig. 6) is adapted to engage and disengage the direct drive between the driven shaft 90 and the shaft 18 which latter is common to the primary and secondary units. This direct drive must not be initiated when a complete drive is established through the secondary and tertiary units. Therefore, it must be a condition precedent to estab- 99 thereby preventing the loss of lubricant from, or the entrance of dirt and chips into said box. An additional spherical portion I61 is provided at the lower end of the lever I64 that cooperates with a socket I68'keyed to a coaxial extension I69 of shaft-I48. The distance between the spherical portions I65 and I61 is greaterthan that between the portion I61 and the center of extension I69. Accordingly, the degree of'movement of the lever I64 that is transmitted to the extension I69 will be amplified so that a substantial angular turning or axial shifting of shaft I48 may be efiected with a relatively small movement of lever I64. The one side of socket I68 is provided with an H-shaped groove .I10 (Fig. 8) into which the one end of a pin I1I (Fig. 16) is adapted to fit. This construction requires the lever I64 to be returned to a neutral position before the shaft I 48 can be and is connected to a coaxial extension I14 of a I sleeve I5I in substantially the same manner as lishing the direct drive that either the element "86 or 93 be in a neutral position. In as much as the bearing I46 that controls the movement of 1 element 93' is moved axially with sleeve I5.I between two :limiting positions through a medial the member I55 (Figs. 8 and 13) must be aligned with the slot I60 in the connecting element I6I prior to such shifting of sleeve I I.

The angular position of the portion of box 99 which houses the extensions I69 and I14 relative to the main portion of the box 89 conveniently locates the gear shifting levers I63 and I64 abreast of the work-supporting table W, but spaced therefrom sufiiciently to prevent chips from the working operation interfering with the actuation of said shifting levers.

When a given gear combination within the transmission has been set up by shifting the levers I63 and I64, it is necessary to manually shift the clutch 63 into engagement and'to simultaneously release the brake 65. tion is accomplished by reciprocation of the rod I02 within the housing 99 (Fig. 6). However, it is desirable to provide an interlock between the main clutch shifting rod I02 and all of the gear-'- engaging shifting means 16, 11, 86, 93 and 95, so that upon shifting the gear-engaging means, should any gear combination fail to effect complete engagement, the clutch cannot permanently be engaged. It often occurs that the teeth of the engaging means fall tooth on tooth, thus preventing engagement of a selected gear combination. Therefore, it isdesirable to provide means for temporarily engaging the clutch 63 to effect This dual func-- relative movement between the teeth of the gearengaging means should the above condition arise.

The above-referred-to interlocking mechanism comprises a common interference rod I11 (Fig. 6) having an aperture through which a portion of a link I18 is adaptedto pass. The link I18 is adjacent the bearing I46 is provided with an arrowhead or cam I83 adapted to cooperate with a notched cam surface formed in an abutment I84 integral with the end of one arm of the bellcrank I44.

The surfaces of the arrowhead or cam I83 and the notched cam surface in abutment I84 are angularly related so thatslight movement of the bearing I46 in either direction from its medial or neutral position causes shifting of the interference rod I11 thereby disturbing alignment of the aperture therein with the link I18. The abutment I84 is of such length that it will clear the arrowhead I83 when the bearing I46 is moved sufiiciently in either direction to effect complete engagement of the element 93 with either gears 88 or 82. Accordingly, when a complete. shift of element '83 is made, rod I11 will be returned by spring I82 to the position where its aperture aligns with the link I18.

Referring to Figs. 6 and 12, the link I18 which serves as the interlock between the gear-combination engaging means and the main clutch 63 is constructed to permit temporary engagement of the main clutch even though the link I18 abuts against the side of the interference rod I11 instead of passing through the aperture therein. Accordingly, the link I18 is in two parts, one portion I85 of which is guided by guides I86 constructed on the base of the box 99. A similar pair of guides I81 is likewise mounted on the base of the box 88 in alignment with the guides I86, and they slidably receive the other portion I88 of link I18. The portion I88 is provided with a finger portion I89 adapted to pass through the aperture in the interference link I11 when the two become aligned. The ends of portions I86 and I88 of link I18 that face each other ,are

a bored, counterbored, and tapped to receive a connected to the bell crank I4I that is manually operated by lever I43 to effect the shifting of the clutch 63 and the brake 65. The link I18 and the aperture in the interference rod I11 must be in alignment before the former will pass through it. Each of the racks I30, I36, I31 and I38 is provided on its one side with notches or cam surfaces [19, equal in number to the positions it will assume during its normal movement while selectively shifting the gear-engaging means. The common interference rod I11 is provided-with slots I80 in its top side (Fig. 10)

through which the racks I30, I36, I31 and I38 V are adapted to pass.

Each of the slots I80 in the rod I11 contains one side wall that is formed as an arrowhead or cam I8I. A spring I82 bears against the one end of the common interference rod I11, tending to urge it to a position where the arrowheads or cams I8I seat in th bottom of the notches or cam surfaces I19 in the side of the racks I30, I36, I31 and I38. In the event that anyof the racks I30, I36, I31 and I38 are not in position for the arrowheads I8I perfectly to seat within the notches I19, the rod I11 will be moved to the right against the action of-the spring I82 as viewed in Fig. 6 causing mis-alignment of the aperture within rod I11 and the link I18. Accordingly, under such conditions, the link I18 will abut against the side of the rod I11, thereby preventing actuation of the bell crank HI, and consequently, preventing the engagement of the clutch 63. The end of the rod I11 screw I80 and a spring I8I. The spring I9I forces the portion I88 away from the portion I85, but permits the portions I88 and I86 to approach each other if the finger I89 abuts the side of the interference rod I11 while continued force is applied to the portion I86. The end of portion I85 opposite that which receives the spring I9I is adapted to be connected to the bell-crank lever I by a cross-head connection including a rectangular block I92 slidingly supported in a groove in the end of the portion I at right angles to the guides I88. A pin I93 mounted in the rectangular block I83 pivotally engages the lever I4I therewith. Therefore, movement of the hand lever I43 to cause permanent engagement ofthe main clutch 83wil1 occur only if the aperture in rod I11 is in alignment with the finger portion I89 of the link I18; otherwise, the finger I88 will abut the side of rod I11 and movement of the lever I43 will cause compression of the spring I8I, eifecting temporary engagement of the clutch 63. However, should complete engagement of the selected gear combination fail to occur, spring I8I will cause separation of the parts I85 and I88 upon release of the lever I43, thereby causing clutch 63 to become disengaged.

An additional interlock is provided between the shifting rack I38 for establishing the direct drive and the rod I05 of the tertiary unit to prevent either one of said means from being operated if the other is in engagement with its respective gears. Referring to Figs. 6, 13, 14 and 17 the interlock comprises a rod I84 connected to the slidable bearing I46 and guided by a groove I85 in a support I86 integral with the base of box 88 (Fig. 13). The rod I94- is provided with a 

